title: Controlled synthesis of nanosized palladium icosahedra and their catalytic activity towards formic-acid oxidation.
abstract: Pd icosahedra with sizes controlled in the range of 5-35 nm were synthesized in high purity through a combination of polyol reduction and seed-mediated growth. The Pd icosahedra were obtained with purity >94 % and uniform sizes controlled in the range of 5-17 nm by using ethylene glycol as both the reductant and solvent. The studies indicate that the formation of Pd nanocrystals with an icosahedral shape was very sensitive to the reaction kinetics. The success of this synthesis relies on the use of HCl to manipulate the reaction kinetics and thus control the twin structure and shape of the resultant nanocrystals. The size of the Pd icosahedra could be further increased up to 35 nm by seed-mediated growth, with 17 nm Pd icosahedra serving as seeds. The multiply twinned Pd icosahedra could grow into larger sizes, and their shape and multiply twinned structure were preserved. Thanks to the presence of twin defects, the Pd icosahedra showed a catalytic current density towards formic-acid oxidation that was 1.9 and 11.6 times higher than that of single-crystal Pd octahedra, which were also fully covered by {111} facets, and commercial Pd/C, respectively.
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, School of Chemistry & Biochemistry and School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332 (USA); Engineering Research Center for Nanophotonics and Advanced Instruments, Ministry of Education, Department of Physics, East China Normal University, Shanghai 200062 (PR China).
authors.forename: Tian
authors.initials: T
authors.lastname: Lv
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Sang-Il
authors.initials: SI
authors.lastname: Choi
authors.forename: Miaofang
authors.initials: M
authors.lastname: Chi
authors.forename: Jing
authors.initials: J
authors.lastname: Tao
authors.forename: Likun
authors.initials: L
authors.lastname: Pan
authors.forename: Cheng Zhi
authors.initials: CZ
authors.lastname: Huang
authors.forename: Yimei
authors.initials: Y
authors.lastname: Zhu
authors.forename: Younan
authors.initials: Y
authors.lastname: Xia
mesh_terms: D002384:Catalysis; D004563:Electrochemistry; D005561:Formates / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D010316:Particle Size
chemical_list: D005561:Formates; C030544:formic acid; D010165:Palladium
keywords: electrochemistry; nanostructures; oxidation; palladium; synthesis design